Across: A: C across + E across.
C: a cubic number.
E: a square number.
G: this square number equals the product of the digits of A down.
I: a square number.
J: a palindrome.
L: a prime number.
M: a prime number.
N: M across plus the digit sum of L across.

Down: A: a prime number.
B: a palindrome.
C: the digit product of C down is a divisor of G across.
D: A down + E across.
F: yhe product of the digits of A across.
H: M across + G across.
I: a perfect number (the sum of all of its divisors, including 1, but excluding itself).
K: a palindrome.
L: a square number.